Signaling apparatus



W.v L. WALKER.

SIGNALING APPARATUS.

APPLICATION FILED APII. II, 1917.

1,349,305., Patented Aug. 10,1920.

l/V, WHL/1ER WILLIAM L. lAll'lKliilft; 0F NEW YORK, N. Y.

SIGNALIN G APPARATUS.

speiacation of Letters Patent.

r Patented Aug. 10,1920.

Application filed April 11, 1917. Serial No. 161,179.

To all whom t may concern:

' Be itknown that I, WILLIAM L. WVALKER,

i acitizen of the United States, and resident of New York, in the county of New York and State of New York, have invented new and useful Improvements in-Signaling Ap` paratus, of which the following is a specification.

This invention relates to electrical signal? ing apparatus for receiving sound disturbances and the like, whether above or below the average audible range and whether in code or otherwise, and more particularly the invention relates to submarine signaling apparatus adapted to detect sound disturbances beneath the surface of a body of' water and to transmit the disturbances to a distant point.

Of the many types of apparatus heretofore vproposed forsubmarine signaling, most' of th em have comprised either a microphonic device or an electromagnetic device for transforming the sound disturbances into electrical disturbances in order to transmit the signals from the receiving device to a distant point. The electromagnetic devices have been more or less heavy and the movbeen adapted to respond readthroughout a limited range of frequencies. 'Moreover, the electromagnetic devices have not been suiciently sensitive to detect the fainter vdisturbances. such as the sound disturbances produced by a distant vessel. The microphonic devices have notbeen wholly satisfactory for the reason that they are ining parts have herently delicate and therefore not adapted to reproduce heavy sound disturbances which produce a large movement of the sound diaphragm orV other sound responsive devices. Moreover, the microphonic devices have not been capable of distinguishing between sounds of different characters and of widely different intensities.

It is vthe principal object of the present invention to overcome the disadvantages inherent in the above and other types of apparatus and to provide means for receiving sound disturbances andthe like, of whatever nature, which -is exceedingly sensitive, which will respond to disturbances throughout an turbances is not exceedingly wide range of frequencies and intensities, which Will readily distinguish between the various kinds of sound such as the sounds produced by submarines of different types, surface vessels of different types and sizes, code signalsv of various intensities and frequencies and which is also adapted to receive and reproduce speech. Another object ofthe invention is to control the pressure w1thin a sound-box so that as the soundboX is submerged in a bodyof water with the outer surface of the sound diaphragm in contact With the water the pressure of the .Water on the outside of the diaphragm is counterbalanced by the pressure produced on'the inside of the sound-box, the pressure Within the sound-box preferably being regulated automatically as the sound-box is raisedv and'lowered in the water. A further object [of the invention is to provide, in novel combination with my improved sound detector, means for reproducing and accurately amplifying the electrical variations produced-by the improved sounddetect'or, whereby the `character of the sound disonly maintained in convertingthe sound disturbances into electrical disturbances but whereby the electrical disturbances are reproduced and amplified so that the precise character of the sound disturbances is manifested by the sound' reproducing device or other indicating or recording 4instrument of the system.

Other objects of the invention will be apthe accompanying drawings, in Which- Figure l is a side elevation of the preferred embodiment of my invention, parts being broken away and parts being shown in section, and the electrical portion of the system being shown Fig.- 2 is a front elevation of the sound detecting apparatus shown in Fig. l. The particular embodiment of my invention, chosen for the purpose of illustration, comprises a sound-box l having an opening in the forward side over which a diaphragm 2 is mounted by suitable means such as the annular collar 3, -`one or more rubber gaskets 4 or other suitable sealing means preferably being provided between the collar 3 diagrammatically; and

may be of any ordinary and the box 1, either on one or both sides of the diaphragm 2. At the central portion of the diaphragm 2 is attached one end of a bell-crank 6, the bell-crank being pivotally mounted intermediate its ends upon a bracket 7 extending from the lower side of the sound-box, the bell-crank preferably being mounted near its upper end so as to magnify the movementJ of its lower end. On the lower end of the bell-crank 6 is mounted an electrode 8, the electrode preferably being secured to the end of the bell-crank 6 by means of a nut 9 formed integrally with the electrode 8, and a nut 11 for locking the electrode 8 upon the bell-crank. Thediaphragm 2 and bell-crank 6 are preferably of conducting material so that current may be transmitted therethrough from the electrode 8 to the interior of the sound-box. Through an opening 12 in the bottom of the sound-box extends an electrode 13, the electrode being held in position by means of a collar 14 threaded into a flange 16 extending from the bottom of the sound-box. The collar 14 is preferably of insulating material, and the opening 12 is somewhat larger than the electrode 13 so that the electrode is maintained out of electrical contact with the sound-box. Within the space 17 packing material is preferably provided in order to render the sound-box water-tight at this point.

At the top of the sound-box is provided a tubular extension 18, to the upper end of which is connected a pipe 19 leading upwardly above the surface of the water. To the side of the tubular extension 18 is connected an elongate chamber which, as illustrated in the drawings, comprises a horizontal portion 22, an elbow 23 and a vertically depending portion 24. The portion 24 is open at its lower end, thereby affording a passage between the exterior and the interior of the sound-box. extension 18 above the lateral pipe 22, is preferably provided an air-'tight plug 26 hermetically to seal the sound-box from the pipe 19 leading upwardly above the surface of the water. i

The electrical portion of the system for transmitting the electrical disturbances produced by the submerged detector to a dis-v tant point, comprises' an audion 27, which type but which preferably has three electrodes, namely, two output electrodes and a current controlling electrode for controlling the flow of current between the output electrodes. 'The particular form of audion illustrated in Fig.' 1 comprises an evacuated container 28, an electrode 29 which may be in the form of a at plate, an incandescent electrode 31, and a. current controlling electrode 32 in the form of a grid interposed between the electrodes 29 and 31, the latter electrodes constituting In the tubular the output electrodes. A battery 33 is provided for heating the filament 31 and to the output electrodes 29 and 31 is connected the output circuit 34. The output circuit 34 includes a source of current 36 and a current responsive device. The current responsive device may comprise, for example, an ammeter, an oscillograph or a, telephone receiver, and in the drawings I have illustrated both an ammeter 37. and a telephone receiver 38, either of which is adapted to be connected in the output circuit by means of a switch 39. At least one of the submerged electrodes 8 and 13 is connected to the audion, preferably to the current controlling electrode 32, and in the particular embodiment of the invention illustrated in the drawings I have shown the submerged electrodes 8- and 13 connected respectively to the electrode 31 and the current controlling electrode 32 of the audion.

In accordance with one of thecardinal objects of the inventio-n the electrodes 8 and 13 are formed of dissimilar metals such ,as zinc and copper or preferably steel and Monel metal which, when submerged in water and particularly in salt water, are adapted to produce a difference of potential therebetween by virtue of galvanic action. The electrodes 8 and 13 are preferably disposed in close proximity so that the distance therebetween is exceedingly short, although for detecting sounds of great intensity the electrodes may be separated a considerable amount. Moreover, the electrodes may, if desired, be so disposedas normally to be in light contact with each other so that a vi bration of the diaphragm 2 through a small range will vary the degree of contact between the electrodes light contact to a heavy contact, this arrangement being particularly suitable for the detection of certain kinds of relatively feeble or high pitched sounds such as those produced by certain types of submarines. The galvanic action between the electrodes exists when the electrodes are in contact inasmuch as the area of contact therebetween is' preferably very small and the contact surfaces are preferably slightly oxidized so as to form a resistance between the electrodes when in contact, the oxidization produced by the atmosphere and water ordinarily being sufficient for this purpose.

When the electrodes are disposed in contact with each other the galvanic action resulting from the two electrodes of dissimilar galvanic materials immersed in the galvanic iuid may be supplemented by a microphonic action .by employing a source of current in the circuit between the electrodes and the audion. I therefore preferably provide a source of current 41 in the circuit 42 leading from the. submerged electrodes 8 and 13 to the audion electrodes 31 and 32, a switch from an exceedingly y 43 being provided to include or exclude the source of current 41 in or from the circuit 42. However, it is to be understood that notwithstanding the fact that I may, if desired, employ a source of current in the cir-` cuit 42 so that the electrodes 8 and 13 may actmicrophonically, the primary and important function of the electrodes 8 and 13 is to produce a galvanic action and for most purposes the source of current 41 is excluded from the circuit.' Another function of the battery 41, when this battery is included in the circuit 42, is to impress a constant potential upon the current controlling electrode 32, the action of the audion 27 being more delicate and accurate when the potential is thus impressed. While either a positive or a negative potential upon the current controlling electrode 32 will improve the action of the audion, the best results are obtained by employing a positive potential, and I therefore preferably connect the positiveter minal of the battery 41 to the current controlling electrode 32 through the galvanic electrodes 8 and 13.

In order to render the mode of operation of the apparatus more apparent the following fundamental characteristics of a galvanic cell are set forth. The smaller the internal resistance, the greater the current for a given external circuit. The magnitude of the internal resistance depends upon the size of the electrodes, upon their distance apart,

' and upon the specific resistance of the elec- The internal resistance is diminished by increasing the area of the electrodes or by decreasing the distance between them. The E M F. gives rise to the current, and also to the various potential differences in all tro'lyte.

parts ofthe circuit.v It may be said that current flows by reason of the potential difference or that the potential differences arise byreasonof the current flow.

he operation of the apparatus is as follows: The pipe 19 is intended to function both as a support for the detecting apparatus connected to the lower end thereof and also to inclose the conductors leading from the sound-box -to 'the audion. In order to support the apparatus at a definite depth the collar 44 is provided on the pipe 19. As the sound-box is lowered in the Water the water rises in pipe 24 and compresses the air within the sound-box, thus counteracting the ressure of the water on the outside of the iaphragm 2. By suitably determining the length of the pipe 24 and the level of vsure in the sound-'box at its connection yvith the sound-box, the ypresmay be made either equal to or greater or less than the pressure on the outside of the diaphragm 2.v As the sound disturbances impinge upon the diaphragm the electrode 8 is moved to and from the electrode 13 by Ifleans of the bell-crank 6. When the diaany given depth" phragm lis at rest and the electrodes 8 and 13 are at rest with respect to each other,a consta-nt potential is produced therebetween by virtue of the aforesaid galvanic action. The current produced by this lpotential varies with the distance between the electrodes, the current decreasing. as the distance increases, and

by movement of the diaphragm the current between the electrodes is caused to vary precisely 'in synchronism with the diaphragm movement. This variation of current is transmitted to the audion 2T over circuit 42 and produces variations of current How in the outp'ut circuit 34 in synchronism with the soungl variations influencing the diaphragm.. By virtue of the inherent character of the galvanic detector the character of the sound waves impinging upon the diapphragm is maintained without distortion in the electrical waves produced in the circuit 42 and by virtue of the inherent delicacy of the audion 27 the variations of current produced in the output circuit 34 possess the same character. By employing a suitable indicating or recording device in the circuit 34, such as an oscillograph or even a sensitive telephone receiver, the nature and location of a source of sound can be accurately ascertained by the character and intensity -of the received impulses.

The dissimilar electrodes 8 and 13 are preferably so connected to the audion as to tend to increase the positive charge on grid 32, so that theV current in circuit 34 will increase With an increase of potential produced by the galvanic electrodes. Thus the positive lpotential continuously impressed upon the current controlling electrode 32, by the vbattery 41 when in circuit, is increased and decreased as the galvanic'electrodes 8 and move 'to and from each other. Moreover, when. the galvanic electrodesare sufficiently close together to produce a microphonic action, the microphonic 'and galvanic actions are cumulative, that is,

the two actions take lace simultaneously in the same direction. his is due to the fact that the positive potential impressed on current controlling electrode by battery 41 increases as the resistance and consequent potential drop across the galvanic electrodes decreases when the galvanic electrodes move toward each other.

One of the principal reasons for the superiority` of the present apparatus over microphonic and other types of apparatus, I believe to'be due to the fact that the range of movement of the galvanic electrodes may be made as eat as desired by locating the phragm. For example, the range of movement could be made as reat as a foot or more, the sensitiveness o the apparatus being rendered correspondingly great. A mias the distance is varied crophone on the contrary, has a relatively small range ot., ovement inasmuch as the contacts must b-maintained at all times and is therefore adapted neither to receive relatively strong sound disturbances nor to receive sound waves throughout a wide range of intensities.

I claim:

1. Signaling apparatus comprising wave responsive means, and a pair of electrodes of dissimilar materials adapted to produce a difference of potential therebetween when immersed in a galvanic fluid, one of the electrodes being connected to the wave responsive means so as vto be moved4 relatively to the other electrodev by waves impinging upon the wave responsive means.

2. Signaling apparatus comprising a diaphragm, a pair of electrodes of dissimilar materials adapted to produce a difference of potential therebetween when immersed in a galvanic fluid, and means for connecting one of the electrodes with the diaphragm so that movement of the diaphragm produces movement of the one electrode relatively to the other electrode.

3. Signaling apparatus comprising a diaphragm, a pair of electrodes of dissimilar materials adapted to produce a difference of potential therebetween when immersed in a galvanic fluid, a lever arm connecting with the diaphragm and one of th electrodes respectively, and means for pivotally mounting the lever arm so that movement of the diaphragm moves the one electrode towardl and from the other electrode.

4. Signaling apparatus comprising wave responsive means, a pairof galvanic electrodes of dissimilar materials adapted to produce a difference of potential therebetween when immersed in a galvanic fluid, one of the electrodes being connected to the wave responsive means so as to be moved relatively to the other electrode by waves impinging upon the wave responsive means, anaudion having two output electrodes'and an electrode for controlling the current flow between the output electrodes, an output circuit connected to the output electrodes, a current responsive device in the output circuitand means for transmitting potential from one of the galvanic electrodesto the current controlling electrode of the audion, whereby motion of the current responsive means produces a variation in the potential of the current controlling electrode thereby affecting the current responsive means.

5. Signaling apparatus comprising wave responsive means, a pair of galvanic electrodes of dissimilar materials adapted to produce Ia difference of potentialu therebetween when immersed in a galvanic Huid, one of the electrodes 'being connected to the wave responsive means so ras to be moved relatively to the other electrode by waves output electrodes of the audion,

impinging upon the wave responsive means, an audionhaving two output electrodes and an electrode for controlling the current iiow between the output electrodes, an output circuit connected to the output electrodes, a current responsive device in the output circuit, and means for electrically connecting the galvanic electrodes respectively to the current controlling electrode and one of the whereby motion of the current responsive means produces a variation in the potential of the current controlling electrode thereby affecting the current responsive4 means.

6. Signaling apparatus comprising wave responsive -means, a pair of galvanic electrodes of dissimilar materials adapted to produce a difference of potential therebetween when immersed in a galvanic fluid, one of the electrodes being connected to the wave responsive means so as to be moved relatively to the other electrode by waves impinging lupon the wave responsive means, an audion having two output electrodes and 'an electrode for controlling the current flow between the output electrodes, one of the output electrodes being an electron emitting electrode, an output circuit connected to the output electrodes, a current responsive device in thel output circuit, an input circuit connecting the galvanic electrodes respectively with the electron emitting and current controlling electrodes, and a source of current in the input circuit tor producing a potential on the current controlling electrode and for producing acurrcnt How in the input circuit, whereby motion of the current responsive means is manifested in the current responsive means by virtue 'of both galvanic and micropbonic action of the galvanic electrodes.

7. Submarine signaling apparatus ,pomprising a water-tight housing having an opening in one side, a sound responsive diaphragm mounted over the opening, an electrode at least a part Yof which is disposed on the outside of the housing, a second electrode connected to the diaphragm so as to be moved relatively to the I'irst electrode by vibration of the diaphragm, the second electrode extending at least into proximity to the said part of the first electrode.

8. Submarine signaling apparatus comprising a. water-tight housing having an opening in one side, a sound responsive diaphragm mounted over the opening, an electrode extending through the housing, a second electrode extending at least into proximity to the part of the first electrode disposed outside ,o the housing and being connected to the diaphragm so as to be moved relatively to the first electrode by vibration of the diaphragm.

9. Submarine signaling apparatus comprising a water-tight housing having an the diaphragm.

to the diaphragm'so as to 'be moved Arelatively to the first electrode by vibration-of Signed 'by me .at Boston, Massachusetts, this 7th/day of April, 1917.

WILLIAM L. WALKER. 

